Download 8 Birds II

Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Lung tissue is denser than
mammalian lung tissue
Conchae warm and clean
air on intake and retain
moisture on exhalation
Air sacs occupy
up to 20% of the
body cavity
Class Aves (birds) II
One-way flow of
(always oxygenated)
air over bird lungs
 more efficient than
two-way flow in
mammalian lungs
4-chambered heart
(like mammals and
crocodiles)
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Circulation
• 4-chambered heart
• largest hearts relative to body size
– can be twice the size of mammalian hearts
• heart size correlated with speed of
flying, diving, altitude, and cold climates
• can more fully drain ventricle compared
to mammals
• high blood pressure
– subject to heart failure in times of stress
1
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
mouth
crop – storage chamber
- horny tongue
- few salivary glands
short pharynx
esophagus – long and elastic
stomach
- proventriculus (enzymes)
- gizzard (grinds food)
Fig. 39.11 Page 891
Fig. 39.11 Page 891
Owls, hawks and kingfishers regurgitate
bones, fur and feathers
Gizzard
muscular chamber lined with rough keratin
contains sandy grit (ingested by the bird)
best developed in seed-eating birds
pancreas
small intestine
pellets are formed in the proventriculus
heart
liver
gizzard
2
duodenum
small intestine
caeca – fermentation chambers
large intestine
cloaca
receives ureters, genital ducts
& large intestine
reabsorbs water
Fig. 39.11 Page 891
Fig. 39.11 Page 891
Excretory System
Nitrogenous waste excreted as uric acid
•
excrete uric acid into cloaca
•
excess water reabsorbed in cloaca
•
forms white paste and mixes with feces
Excess salt
E
lt secreted
t d by
b special
i l salt
lt glands
l d
•
special salt glands above each eye
secrete a high concentration of salt
•
salt solution excreted via internal or
external nostrils
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Metabolism
• High resting metabolic rate (songbirds
have the highest BMRs of all
vertebrates)
• During flight, metabolic rate 10X BMR
• However,
However flight is energetically very
efficient
– a song bird flying 1 km expends <1% of the
energy a mouse would use to run the same
distance.
3
Birds have high basal metabolic rates
Humans
BMR for a 70 kg male is about 1560 – 1680 kcal/day
23 kcal/kg/day
Mass-specific basal rate of metabolism as a function of body mass
Species
Mass (gms)
kcal/kg/day
Trumpeter Swan
8900
47
Brown Pelican
3500
75
Common Raven
850
108
American Kestrel
110
157
White-crowned
Sparrow
27
324
House Wren
11
589
Rufous Hummingbird
3.5
1600
O2 consumption as a function of body weight
all birds
nonpasserines
flying fox
flying fox
fruit pigeon
mammals
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
4
Endothermic vs ectothermic
Endothermic vs ectothermic
• Endothermic - use their own body heat to
maintain a warm, constant body
temperature (birds and mammals)
• Endothermic - use their own body heat to
maintain a warm, constant body
temperature (birds and mammals)
• Ectothermic – use environmental
temperature to regulate body temperature
(invertebrates, fish, amphibians, reptiles)
Thermoregulation
1. Heat production –
The primary means for increasing heat
production for birds is shivering.
Thermoregulation
2. Evaporation – birds lack sweat glands
so evaporation can occur only via
respiratory system:
- panting
- gular flutter
The large flight muscles (pectoralis) as
well as the leg muscles play an important
role in generating heat by shivering.
Thermoregulation
3. Feathers
- number of feathers
varies seasonally;
more during the winter
than the summer
Thermoregulation
4. Posture
to reduce heat loss:
- withdraw feet into plumage
- tuck head & neck under wing
- position of feathers
controlled by dermal
muscles
5
Thermoregulation
4. Posture
to reduce heat loss:
- withdraw feet into plumage
- tuck head & neck under wing
Thermoregulation
5. Legs & Feet
• limited heat loss in cold weather because of
thermal counter-current
to increase heat loss:
- extend wings
Counter current heat exchange
Thermoregulation
5. Legs & Feet
• limited heat loss in cold weather because of
thermal counter-current
• can radiate heat during hot weather:
increased blood flow
Thermoregulation
5. Legs & Feet
• limited heat loss in cold weather because of
thermal counter-current
• can radiate heat during hot weather:
increased blood flow
• storks & vultures defecate
on legs to increase heat loss
by evaporation
Thermoregulation
6. Social Behavior
- Communal roosts, e.g., Willow Ptarmigan can
burrow in the snow up to 21 hrs a day in cold
weather.
6
Class Aves (birds) II
Summary of Thermoregulation
1. Heat production – shivering
2. Evaporation - gular flutter & panting
3. Feathers
- number of feathers varies seasonally
- position of feathers controlled by dermal muscles
4. Posture
- to reduce heat loss: withdraw feet; tuck head under wing
- to increase heat loss: extend wings
5. Legs & Feet
- thermal counter-current
- increased blood flow in hot weather
6. Social Behavior
- communal roosts
- huddling
Birds have
excellent vision!
Birds have good
hearing abilities.
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Vision
•
•
•
•
Vision is the dominant sense in birds
Eyes are large - must turn their heads
Birds can see 2 – 3 x better than humans
Color vision well-developed in diurnal
birds - many cones
• Nocturnal birds have few cones and many
rods
• Most birds can see UV
• Some birds can see polarized light
Hearing ranges of birds:
For most birds, hearing is best at
frequencies of 1 - 4 kHz
(humans: 0.5 – 5 kHz), but some
birds are able to detect higher
frequencies (up to 10 - 12 kHz).
The ability of birds to discriminate
differences in the frequency of
sounds & to detect gaps between
sounds is generally similar to
humans.
7
Owls note the differences in intensity and
timing of sounds between the two ears.
Some owls have asymmetrical ear openings, allowing them to
accurately note differences in the intensity and timing of sounds in both
the horizontal (azimuth) and vertical (elevation) planes.
Some owls have asymmetrical ear openings, allowing them to
accurately note differences in the intensity and timing of sounds in both
the horizontal (azimuth) and vertical (elevation) planes.
Barn owls can
capture a mouse in
total darkness
based on sound
alone.
Woodpeckers can hear
grubs moving below the
bark of trees and can
detect low-frequency
sounds that precede
earthquakes.
th
k
Birds lack conspicuous external ears.
Instead, they have specialized feathers
called auriculars or ear coverts.
8
Olfaction
Except for flightless birds, ducks and vultures,
birds have a poor sense of smell.
“Dumb as a dodo”
Dodo (Raphus cucullatus)
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Mauritius
The great auk (Pinguinis impennis)
- Hunted to extinction by 1844
?
9
Birds have big, complex brains!
• Bird brains are larger relative to body size than
all other vertebrates except mammals
• Large motor-control areas (cerebellum), optical
centers and song-control centers (cerebral
hemisphere)
What is “intelligence”?
19th
century
modern view
Intelligence is the ability to “learn how to
learn” – to solve problems of a given class
correctly when first confronted, and then to
solve problems of a similar nature with
increasing speed when they are encountered
again.
Insight involves the ability to envision one's
actions and their consequences.
Corvids have
shown a marked
ability to solve
problems.
perch
string
meat
Raven (Corvus corax)
Raven
10
Black-capped Chickadees and Nuthatches can
distinguish empty sunflower husks from full
ones by weight alone.
... but chickens, doves, cats and rabbits don’t do as
well in tests that involve reasoning or learning.
Blue Jays have learned to avoid
toxic Monarch butterflies by
watching other Blue Jays in
adjoining cages.
Crows and parrots often perform as well as dogs in
tests that involve reasoning or learning ...
Blue Jays can locate food better
than cats or monkeys.
Great Tits learned how to open milk bottles ...
11
... and other species learned the behaviour by imitation.
House Sparrows have learned to open
automatic doors to grocery stores and cafés
by hovering in front of the sensor.
Blue Tit
Great Spotted Woodpecker
European Starling
Parrots can learn 100’s to 1000’s of different calls
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Communication
Signal – behaviour that alters the
behaviour of the receiver in a way that
benefits the sender
Display – ritualized signal that conveys a
specific message
Communication
• Passive communication: plumage
patterns
– colors
– shape
– pattern
• Active communication:
– courtship displays
– territorial displays
– sound
• calls
• songs
• non-vocal sounds
12
Passive communication: plumage patterns
colors
shape
pattern
Passive communication: plumage patterns
colors
shape
pattern
Grouse
male vs female
young vs adult
Passive communication: plumage patterns
colors
shape
pattern (incl. composition, number, size...
Communication
• Passive communication: plumage patterns
– colors
– shape
– pattern
• Active communication:
– courtship displays
– territorial displays
– sound
• calls
• songs
• non-vocal sounds
Communication
• Passive communication: plumage patterns
– colors
– shape
– pattern
Grouse displaying
• Active communication:
– courtship displays
– territorial displays
– sound
• calls
• songs
• non-vocal sounds
Mostly innate and
highly stereotyped
Communication
• Passive communication: plumage patterns
– colors
– shape
– pattern
• Active communication:
– courtship displays
– territorial displays
– sound
• calls
• songs
• non-vocal sounds
Red-winged Blackbird
shoulder patch
13
Sound
• Calls – short, stereotyped vocalizations; innate
– Alarm – signals danger to other conspecifics
– Contact calls – used to locate mates and young
– Flight calls - keep the flock together
Sound
• Non-vocal sounds
–
–
–
–
–
Storks use bill clattering in courtship
Mute swan hisses and grunts
Woodpeckers peck to defend territories and attract mates
Male grouse attract females by rapidly beating wings
Broad-tailed hummingbirds trill with wings - territorial
Migration
Mass movement of individuals between
breeding and wintering areas
Defining characteristics:
Sound
Songs – complex, often learned
– Territorial
– Attract females
– Species identification
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Not all long-distance movements are migrations
e.g., Albatross fly huge distances when foraging
- not seasonal or predictable
- solitary
• Seasonal (predictable)
• Large numbers of individuals (flocks)
14
Not all long-distance movements are migrations
Movement away from natal area: dispersal
- solitary
- new location unpredictable
Not all long-distance movements are migrations
Movement away from natal area: dispersal
- solitary
- new location unpredictable
Movement away from a food-poor area: irruptions
- not annual
- unpredictable
Migration
- 75% of North American birds migrate.
- 90% of “Canadian” birds migrate outside of
Canadian borders
- Migratory restlessness – controlled by
hormones activated by changing daylengths
- Many individuals use flyways, but these can
change and some individuals do not “follow
the pack”.
Why do birds migrate?
Birds migrate when benefits are higher
than costs (energy and mortality risk) of
using well-separated breeding and
wintering areas.
http://www.birdnature
e.com/allflyways.html
Snowy Owl
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Why do birds migrate?
• Some species migrate south in the winter because
food is unavailable in temperate zone
• Higher reproductive success in temperate vs tropical
areas
Temperate zone:
Abundant food and longer days for foraging in
spring/summer
Food shortages and cold in winter
Tropics:
High density of nest parasites and predators
Mild temperatures and food availability in winter
15
Modes of Migration
•
•
•
•
•
Flight pattern
Time of day
Flight mode
Length of migration
Completeness
Modes of Migration
• Time of day
Modes of Migration
• Flight pattern
– nonstop flights over oceans, deserts,
mountains.
– e.g., American Golden Plovers fly 4,000 km between NE
U.S. and South America
– in bad weather, birds can be grounded for hours or
days (fallouts)
– “hops” of 250-300 km
Modes of Migration
• Flight mode
– diurnal migrants
• often depend on thermal winds or updrafts,
e.g., hawks.
• may depend on diurnal food resources, e.g.,
swallows
– nocturnal migrants
• start about ½ hour after sunset, e.g.,
woodpeckers, vireos, thrushes
• cooler and air less turbulent
• avoid diurnal predators
– soarers
• flight concentrated in mid-day when
thermals occur, e.g., hawks
– powered flight
• often crepuscular (start just before
dawn)
• nocturnal migrants
Why fly at night?
Modes of Migration
• Length of migration
– long-distance migrants
• usually between continents
• e.g., Golden Plover (between NE U.S. and
S.A.)
Modes of Migration
• Completeness
–complete migrants
• entire population migrates
–partial migrants
– short-distance migrants
• within continents
• often elevational changes, e.g., Hermit
Thrush
• some individuals overwinter on
the breeding grounds
16
Modes of Migration
• Flight pattern
How do they do it?
• Orientation – ability to align in an
appropriate direction when released into
unfamiliar surroundings (internal compass).
– nonstop
– “hops”
• Time of day
– diurnal
– nocturnal
• Flight mode
– soarers
– powered flight
• Navigation – ability to find a specific
geographical location from a known starting
point.
• Length of migration
– long distance
– short distance
• Completeness
– complete migrants
– partial migrants
Orientation
• Sun compass – can tell direction from the
Sun’s position because of an internal
circadian clock.
Polarization pattern
– e.g., at 7:00 AM a bird “knows” the Sun should
be in the east, a few degrees above the
horizon.
– also, many birds can detect the polarization
pattern,
tt
and
d this
thi can be
b used
d on days
d
with
ith
significant cloud cover.
• Star compass – the north star (Polaris)
gives an absolute point of reference.
• Magnetic compass – can detect the
Earth’s magnetic field.
Orientation
• Sun compass – can tell direction from the
Sun’s position because of an internal
circadian clock.
– e.g., at 7:00 AM a bird “knows” the Sun should
be in the east, a few degrees above the
horizon.
– also, many birds can detect the polarization
pattern,
tt
and
d thi
this can be
b used
d on days
d
with
ith
significant cloud cover.
• Star compass – the north star (Polaris)
gives an absolute point of reference.
• Magnetic compass – can detect the
Earth’s magnetic field.
90° to Sun
Navigation
• Navigational landmarks
– coastline
– mountain ranges
– large rivers
• Magnetic anomalies
• Local landmarks
17
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Dispersal
Natal dispersal – the first movement
away from the nest area (typically,
high mortality).
B
Breeding
di dispersal
di
l – movements
t off
adults between different breeding
locations.
Amniotic egg
Dispersal
Not all birds migrate, but almost all
individuals disperse.
There are two types of dispersal ….
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
Amniotic egg
18
Reproductive System
Males
•
testes small, bean shaped most of year
•
testes enlarge 300 x at breeding season
•
sperm stored in seminal sac
•
most males lack a penis
Birds have a
single ovary
Females
•
only left ovary and oviduct develop
•
eggs fertilized at top of oviduct
•
albumin, shell membrane, shell added during
passage down oviduct
Reproductive behaviour
Monogamy
Most birds are monogamous for one or more breeding seasons and
some are monogamous for life (e.g., swans and geese)
• Monogamy
• Individually defended territories -most birds
parakeets mating
• Colonial breeding - about 13% of all bird
species
• Cooperative
C
ti b
breeding
di – about
b t 250 species
i
• Non-monogamous breeding (<10% of bird
species)
Two kinds of monogamy:
Social monogamy – male and female cooperate in raising young;
>90% of all birds.
Genetic monogamy – male and female are the sole genetic
parents of all the young; rare.
rare
Birds can be either socially or genetically
monogamous, both – or neither.
• Brood parasitism
• Courtship ritual - both sexes participate
Social vs genetic monogamy implies …
Extra-pair copulations
Why?
• forced copulations – waterfowl
• females are often willing and actively seek extra-pair
copulations
- hedge against infertility in primary partner
- increases genetic diversity of young
- might produce young by a higher-quality male
How lack of genetic monogamy is detected
If the DNA of young and putative father do not match
extra-pair copulation
If the mtDNA of young and mother do not match
The bottom line is ….
Genetic monogamy is probably rare
nest parasitism (egg dumping)
19
Reproductive behaviour
• Monogamy
• Individually defended territories - most birds
• Colonial breeding - about 13% of all bird
species
• Cooperative
C
ti b
breeding
di – about
b t 250 species
i
• Non-monogamous breeding (<10% of bird
species)
Individually defended territories
• most territories contain both food and
nesting sites
• some territories contain only nesting sites
• boundaries are dynamic
• males
l typically
t i ll defend
d f d territories
t it i by
b
– song
– visual display behaviour
– active defense
• Brood parasitism
• Courtship ritual - both sexes participate
Reproductive behaviour
• Monogamy
• Individually defended territories - most birds
• Colonial breeding - about 13% of all bird sp.
What are the advantages and
disadvantages of colonial
breeding?
Reproductive behaviour
• Monogamy
• Individually defended territories - most birds
• Colonial breeding - about 13% of all bird sp.
Colonial Breeding
Advantages:
- favored by scarcity of sites safe from predators
- favored by scarcity of sites near abundant food
- cooperative protection from predators
- enhances foraging on ephemeral food supplies
Disadvantages:
- colony may attract predators
- increase the spread of nest parasites (e.g., mites, lice)
- increased competition for food
Cooperative breeding
• breeders defend group territories
• nest helpers – young birds that help feed and defend the nest
• nest helpers benefit by
- raising close relatives (kinship selection)
- creating large territories in which they might breed
• Cooperative breeding – about 250 sp. (< 3%)
Florida Scrub Jay
20
Reproductive behaviour
• Monogamy
Non-monogamous breeding
• Promiscuity – no stable social relationship
• Individually defended territories -most birds
– rare in birds; found in some hummingbirds
• Colonial breeding - about 13% of all bird sp.
• Cooperative breeding – about 250 sp. (< 3%)
• Non-monogamous breeding (<10% of bird sp.)
• Brood parasitism
• Courtship ritual - both sexes participate
Non-monogamous breeding
• Promiscuity – no stable social relationship
– rare in birds; found in some hummingbirds
• Polygyny – one male and several females
• Polyandry – one female and several males
• Polygynandry – both males and females
have multiple mates
Polygyny (one male and several females)
• 2% of all bird species
• males provide little or no parental care
• young are typically precocial
– rare; Smith’s Longspur in North America
Polygyny (one male and several females)
•
•
•
•
2% of all bird species
males provide little or no parental care
young are typically precocial
lekking
– males gather at the lek and display
– females
f
l choose
h
males;
l
high-status
hi h
males
l have
h
multiple mating
– no male parental care
Hatch blind, naked, and
virtually helpless; most
songbirds, hawks, herons,
etc.
Hatch with eyes open, downy
feathers, and are capable of
independent movement within a
few hours; e.g., grouse, quail,
ducks, water birds, shorebirds,
etc.
e.g. sage grouse
21
Non-monogamous breeding
• Promiscuity – no stable social relationship
– rare in birds; found in some hummingbirds
• Polygyny – one male and several females
• Polyandry – one female and several males
• Polygynandry – both males and females
have multiple mates
– rare; Smith’s Longspur in North America
Polyandry
• Polyandry – one female and several males
– 1% of all bird species
– classic polyandry: female lays eggs in separate
nests and males incubate and rear brood
– cooperative polyandry: female lays eggs in one
nest and several males care for young
– reversed sexual dimorphism: females larger and
more colorful than males
Spotted Sandpiper
Spotted Sandpiper (male)
Non-monogamous breeding
• Promiscuity – no stable social relationship
– rare in birds; found in some hummingbirds
• Polygyny – one male and several females
• Polyandry – one female and several males
• Polygynandry – both males and females
have multiple mates
– rare; Smith’s Longspur in North America
Reproductive behaviour
• Monogamy
• Individually defended territories -most birds
• Colonial breeding - about 13% of all bird sp.
• Cooperative breeding – about 250 sp. (< 3%)
• Non-monogamous breeding (<10% of bird sp.)
• Brood parasitism
Brood Parasitism
• Females lay their eggs in the nests of
other birds (the hosts)
• Two types of brood parasitism:
– intraspecific parasitism (“egg dumping”)
• very common
– interspecific parasitism
• European cuckoos
• North American Cowbirds
• Courtship ritual - both sexes participate
22
Reproductive behaviour
• Monogamy
• Individually defended territories -most birds
• Colonial breeding - about 13% of all bird
species
• Cooperative
C
ti b
breeding
di – about
b t 250 species
i
• Non-monogamous breeding (<10% of bird
species)
• Brood parasitism
• Courtship ritual - both sexes participate
Blue-footed boobies and frigate birds
Galapagos Islands 2006
Western grebe - weed dancing
Western Grebe - rushing
Nest sites
trees e.g., Bald Eagle
shrubs, e.g.,
Bushtit
23
Nest sites
cliff ledge:
e.g., Horned puffin
Nest sites
crevices or cliff faces
- e.g., Cliff swallow
on ground e.g., gulls,
terns, loons, ducks
Class Aves (birds) II
Respiratory system
Circulatory system
Digestion and excretion
Metabolism
Thermoregulation
Senses
Intelligence
Communication
Migration
Dispersal
Reproduction
How to identify birds
treeholes e.g.,
woodpeckers
Eight visual categories
1)
2)
3)
4)
5)
6)
7)
Swimmers – ducks, etc.
Aerialists – gulls, etc.
Long-legged waders – herons, cranes, etc.
Smaller waders – Plovers, sandpipers, etc.
Fowl like birds – Grouse,
Fowl-like
Grouse quail
quail, etc
etc.
Birds of prey – Hawks, eagles, owls
Nonpasserine land birds – Kingfishers,
woodpeckers, hummingbirds, swifts, etc.
8) Passerine (perching) birds
What is the bird’s size?
What shape is its tail?
Use some common birds as a “yardstick”.
rounded
forked and pointed
Robin
Pigeon
House Sparrow
Quail
Barn Swallow
24
What shape is its bill?
What shape are its wings?
Hawk
Tern
Sparrow
Tern
Hawk
Warbler
How does it behave?
House Wren
Does it climb trees?
Flycatcher
jerks
down
headfirst
Woodpecker
Nuthatch
How does it fly?
spirals
Brown Creeper
Does it swim?
soar
Up and down
hover
Mallard
Loon
Kingfisher
Northern Flicker
Hawk
25
Does it dive?
Does it wade?
Sandpiper
Mallard
Merganser
Merganser
Bird Topography - What are its field marks?
Great Blue Heron
What are its field marks?
Color patterns
i.e. tibia!
Western Meadowlark
What are its field marks?
Color patterns
Wood Duck
What are its field marks?
Color patterns
American Wigeon
26
What are its field marks?
Tail patterns
Western Kingbird
Eastern Kingbird
What are its field marks?
Tail patterns
What are its field marks?
Tail patterns
Western Kingbird
What are its field marks?
Tail patterns
Rufous-sided Towhee
Dark-eyed Junco
What are its field marks?
Tail patterns
American Redstart
What are its field marks?
Rump patches
Cliff Swallow
27
What are its field marks?
Eyestripes and eye-rings
Mountain Chickadee
Black-capped Chickadee
What are its field marks?
Wing bars
Ruby-crowned kinglet
What are its field marks?
Wing Patterns
Herring gull
28